SOME ELECTRONIC CONTROL UNITS FOR OPERANT BEHAVIOR STUDIES:I. A RESPONSE AND REINFORCEMENT CONTINGENCY TRANSLATOR'

W. N. SCHOENFELD, W. W. CUMMING, E. HEARST,M. WAINE, A. G. SNAPPER, and P. HAAS

COLUMBIA UNIVERSITY

We have developed in our laboratory a versatile translator for response events and re-inforcement contingencies. We have used it extensively, and it has reached a stage of de-velopment in which its functioning is of high reliability. The unit is a central one aroundwhich various types of auxiliary apparatus may b'e employed to produce a wide variety ofexperimental conditions. In subsequent apparatus notes, we will describe several of thesupplementary systems we are using in the study of temporal schedules of reinforcement.Among the functions of the translator the following may be noted: (a) it accepts re-

sponse data electronically (in the form of pulses); (b) it passes these data to recordingdevices; (c) on external signal, it provides a timed reinforcement for the next response orfor any number of subsequent responses; (d) on another external signal, it removes rein-forcement availability; (e) on an external panel, it permits manual testing of each of itsfunctions.The control unit has a number of advantages for behavior researches, including the ability

to handle very high rates of responding (surpassing the response rate of any known organ-ism, and approaching, if not surpassing, the limit of any currently available recording orprint-out device). It can be driven by any experimental programing system at virtually un-limited speed (up to 100 kilocycles). It is compact, and provides long trouble-free operation.The circuit diagrams of the apparatus are given in Figs. 1 and 2, each accompanied by an

index of components. The operation of both circuits may be traced as follows:(1) The response pulse is generated by closure of the pigeon key (K), or, if switch SI is

thrown, key pecks may be manually simulated by push button BI on the control panel. K, ofcouse, may be any manipulandum operating as a switch.

(2) Each closure of K operates relay RYI, feeding a response pulse into the one-shot (El),which in turn puts out a square wave of consistent amplitude and duration. The latter op-erates the Sodeco response counter through the circuit involving half of tube T1 and relayRY3. The occurrence of a response is also indicated on the panel face by a flash of neonlight N3. The duration of the standard pulse from El is controlled by the magnitude ofcapacitor C2, for which a value must be chosen that provides an output pulse of sufficientduration for the operation of the particular recording mechanism being used. (We havefound 0.05 microfarad a satisfactory value of C2 for both Sodeco counters and Gerbrandscumulative recorders.) Most recording devices have a sizable refractory period which mustbe taken into account in the setting of C2. Response events within the refractory period ofthe recorder can be reinforced by the present system, if so desired. Mechanical counters donot have the resolving power for responses which this electronic system provides, but elec-tronic counters of very short refractory period are available with counting resolution whichcan be made equal to the resolution of the present reinforcement system, if necessary.

The apparatus as described was developed in conjunction with research supported by the National ScienceFoundation under Grants G-3408 and G-5517. Earlier support for design of a first model was given by theEugene Higgins Fund of Columbia University.

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18 SCHOENFELD, CUMMING, HEARST, WAINE, SNAPPER, and HAAS

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ELECTRONIC CONTROL UNITS

(3) The output of El also is coupled to E2, a pulse gate, which will pass or block thenegative-going side of the output pulse of El that operates the reinforcement circuits. Thestate of the gate is determined by E4, a flip-flop (bi-stable multivibrator) controlled froman external programing system. The state of E2 is visually indicated on the control panelby N1, which glows when the gate is open. Pulses from the external programing system areshaped by two Schmitt trigger circuits to insure correct amplitude and rise time for re-liable operation of E4. Figure 2 is the circuit diagram of one such trigger. Operation of aSchmitt trigger requires only grounding of its input, which can be accomplished eithermanually by button B2 or by relay circuit; alternatively, external programing systems maybe used which activate the trigger by electronically generated pulses. There are, of course,two buttons with the function of B2, one at the input to each Schmitt trigger, which pro-duce, respectively, the "pass" and "block" states of E2.

(4) The reinforcement circuit consists of one-shot E3 which operates tube T 1 (the half notused for response counting) in a manner identical with the response-counting circuit. Thisoutput of Tl operates RY2, the contacts of which are RCl and RC2, charging the timingcircuit associated with tube T2. The duration of reinforcement is controlled by the dis-charge time of this circuit and may be set by RI I which controls the holding time of RY4.RY4 operates the feeder and reinforcement counter. The occurrence of a reinforcement isvisually indicated on the control panel by a flash of N2.

Index For Figure IR I-I megohm, 1/2watt CI-.05 mf., 300 v.R2-I megohm, 1/2 watt C2-.05 mf., 300 v.R3-I megohm, 1/2 watt C3-.05 mf., 300 v.R4-1 megohm, 1/2 watt C4- .5 mf., 200 v.R5- 10 K ohm, I watt C5-.25 mf., 200 v.R6- 10 K ohm, I watt C6-.25 mf., 200 v.R7-I megohm, 1/2 watt C7- .5 mf., 200 v.R8-1 megohm, 1/2 watt C8- .5 mf.,200v.R9- 10 K ohm, I watt C9-.25 mf., 200 v.R 10-6.4 K ohm, 2 watt C 10-100 mmf.RI 1-5 megohm, 2 watt(variable)R12-100K ohm, 1/2wattBI -Manual response pushbuttonK-Pigeon keyRY 1-28 volt mercury-wetted-contact relay** RC I -Contacts on RY2RY2- 10 K ohm plate relay RC2-Contacts on RY2RY3-10 K ohm plate relay RC3-Contacts on RY IRY4- 10 K ohm plate relayE I-EECO one-shot Z-8348* NI-NE51 neon bulbE2-EECO pulse-gate Z-8327* N2-NE51 neon bulbE3-EECO one-shot Z-8348* N3-NE51 neon bulbE4-EECO flip-flop Z-8342*S 1-Manual response switch, SPDT toggle DI-diode 1N34AS2- Reset after reinforcement switch, SPDT toggle D2-diode I N34AS3-Power switch D3-diode I N34A"A"--"pass" input from Schmitt trigger T1 - 12AT7 tube"B" -"block" input from Schmitt trigger T2-12AT7 tube

*AIl EECO plug-in circuits are manufactured and sold by the Engineered Electronics Co., 506 East First Street,Santa Ana, California.

**Similar to HG 1042 made by C. P. Clare Co.

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20 SCHOENFELD, CUMMING, HEARST, WAINE, SNAPPER, and HAAS

Figure 2. Circuit diagram of the Schmitt trigger. Two of these auxiliary circuits are used in conjunction withthe translator.

Index For Figure 2

R13-210 K ohm, 1/2 watt C I-50 mmf.R14- 10 K ohm, 1/2 watt C 12-100 mmf.R15- I5 K ohm, I wattR16-220 K ohm, 1/2 watt T3-one-half 12AX7 tubeR17- 33 K ohm, 1/2 watt T4-one-half 12AX7 tubeRI 8-100 K ohm, 1/2 watt T5-one-half 12AT7 tubeRl9-100 K ohm, 1/2 wattR20- 33 K ohm, I watt D4-diode 1N34A"A"-"pass" input to translator B2-Manual pushbuttonH- "pass" input from programmerB+-200 v DC+Duplicate above circuit for "block" pulse using other half of T5.

(5) To accomplish regular reinforcement, switch S2 is opened. If S2 is closed, the oc-currence of reinforcement sends a pulse from the circuit associated with RC2, resetting theflip-flop E4, blocking the gate E2, and preventing further reinforcements until the flip-flop isagain pulsed by the programing system.

(6) We have worked out convenient control panel and chassis arrangements of these cir-cuits which simplify wiring and contribute to the ease of operation. Details are availableon request.

Received October 8, 1959